This invention relates generally to a device for incinerating waste water or waste solution (which water or solution will hereinafter be referred to as "waste liquid"), and more particularly to a waste liquid incinerator capable of efficiently incinerating both waste liquid and waste gas or waste air at the same time. The invention also relates to a method of incinerating waste liquid. A typical waste liquid useful in the invention contains a gas such as ethylene oxide. A typical waste gas useful in the invention is ethylene oxide. Waste air useful in the invention is that containing a malodorous substance such as an unsaturated organic compound.
A great amount of ethylene oxide has been used for the disinfection and sterilization of medical equipment. Used ethylene oxide is treated typically as a waste gas and thus is incinerated. Beside this, ethylene oxide, as being water soluble, tends to be present in a dissolved form in the water within transportation means such as a water seal pump. It is common that such water with dissolved ethylene oxide is stored and eventually incinerated as a waste liquid. Known as devices for incinerating waste liquid are vertical and horizontal incinerators.
A typical horizontal incinerator has a container including a horizontal tubular side wall and a pair of opposing end walls closing the opposite ends of the side wall. One of the end walls is provided with a burner, and the other end wall is with an inlet for waste liquid. The burner flame is jetted horizontally into the container toward the other end wall while waste liquid is sprayed downwardly from the inlet, which allows the sprayed waste liquid to be incinerated. In this type of incinerator, however, waste liquid is sprayed exclusively over the area remote from the burner flame in order to avoid the flame extinction due to the sprayed waste liquid.
Because of the above arrangement, the horizontal incinerators have the following drawbacks: (1) the internal temperature of the container tends to decrease to the extent that it is hard to carry out the complete incineration; (2) it is difficult to design a small-sized container; (3) a large installation space is required; (4) the equipment cost is high; (5) the heat efficiency is low which results in high energy consumption; and (6) a large amount of nitrogen oxide tends to be generated due to a high flame temperature, which may be a cause of photochemical smog, an environmental pollutant, when released into the atmosphere.
A typical vertical incinerator has a container including an upright tubular side wall and top and bottom opposed walls closing the upper and lower ends of the side wall. The side wall is provided at its midriff with a burner, and the top wall is with a waste liquid inlet. This arrangement is disclosed, for example, in Japanese Patent Application Laid-Open No. 4-283309. The burner flame is jetted horizontally into the container while waste liquid is sprayed downwardly from the inlet, resulting in the incineration of the sprayed waste liquid. In this incinerator, waste liquid is again sprayed over the area remote from the burner flame to avoid the extinction of the flame. Because of the arrangement similar to the horizontal incinerators, the vertical incinerators cannot be free of those similar to the above drawbacks (1)-(6).
What is needed, therefore, are an improved incinerator for waste liquid and an improved method of incinerating waste liquid. Such an incinerator and a method should provide better heat efficiency to allow the design of a small-sized incineration container, allow quick heating and rapid vaporization of waste liquid to encourage the complete incineration of the waste liquid, enable the incineration of a large amount of waste liquid in its smallsized container so that a less installation space is required, reduce the equipment cost, reduce the energy consumption while providing dependable heat efficiency and assure a low flame temperature to inhibit formation of nitrogen oxide.